And now, on the eve of that event's 50th anniversary, here come more, dozens of them of every imaginable topic, angle, theory and sentiment, varying in quality from deadly academic to colorfully schlocky.

Why?

The simplest answer is that people buy these books, the appetite for things JFK seemingly insatiable, and publishers always eager to keep feeding it.

But why is that?

Theories abound: the so-called unanswered questions that surround his death, the shimmering Camelot legacy; the Kennedy clan's way of finding trouble. Take your pick.

In large part JFK remains with us because his assassination and its aftermath — Jack Ruby killing Lee Harvey Oswald, little John John saluting his father's coffin — came at us with the visceral immediacy of television and remain locked somehow in our collective memory, our national DNA.

In much the same way that Kennedy helped change the face of politics — especially in the 1960 presidential debates from Studio One at Chicago's WBBM-TV — so did his death (and life) alter the world in bigger ways.

Also, for all of their human failings and frailties, Jack and Jackie Kennedy, Camelot's king and queen, were otherworldly in their beauty and style, and they remain so in their continuing capacity to captivate and to haunt. (See also James Dean and Marilyn Monroe).

The ripple effect is ongoing, with new books to suit any taste. Over the last couple of weeks, I have read some and sampled many others. Here are snapshots and thoughts from that journey.

That Oswald killed Kennedy is impossible to dispute. But Ruby's bullet unintentionally started the series of questions — was Oswald a lone gunman or, as he mysteriously claimed after his capture, "a patsy" — that continue to fuel the Kennedy conspiracy industry. Titles in that category include:

→"The Man Who Killed Kennedy: The Case Against LBJ" by Roger Stone with Mike Colapietro

→"CIA Rogues and the Killing of the Kennedys: How and Why U.S. Agents Conspired to Assassinate JFK and RFK" by Patrick Nolan, with a foreword by Henry C. Lee

→"They Killed Our President: 63 Reasons to Believe There Was a Conspiracy to Assassinate JFK" by that eminent historian Jesse Ventura, with contributors Dick Russell and David Wayne

As put off as I quickly was by those books, I found others much more worthwhile. Here are some of those:

I was charmed by this book, a gathering of spectacular photos, with a foreword by Caroline Kennedy ("To those of us who knew her, she sparkled — and the world she created was one we felt fortunate to inhabit"), finely crafted essays by Michael Quinlin and a great deal of Rose's own writings, such as "God made the world and made us to live in it for a while."

Abraham Lincoln has had 15,000 or so books written about his life. One is 2007's best-selling "Manhunt: The 12-Day Chase for Lincoln's Killer" by James L. Swanson. Now Swanson, who once did some writing for the Tribune, tackles JFK. In his introduction Swanson writes, irrefutably, that "(t)hose who were alive in the fall of 1963 and were old enough then to remember it today shudder at the mere mention of the date." He also writes, "We have strayed too far from the human truths of that day. A wife lost her husband. Two children lost their father. A nation lost a president. … Half a century later, Americans refuse to forget him. We mourn him still."

Perhaps that is another reason for the attraction: the unfinished business, unanswered questions.

"If Kennedy Lived: The First and Second Terms of President John F. Kennedy: An Alternate History" by Jeff Greenfield, Putnam, 272 pages, $26.95

Some yearn to know the later chapters of the book that was Kennedy's life. Political commentator Jeff Greenfield provides what is in essence a novel — and not a bad one —depicting what would have happened had Kennedy survived. Commenting on the day Kennedy leaves Dallas' Parkland Hospital on Dec. 11, 1963, Greenfield has Walter Cronkite say, "I think of myself as a pretty composed reporter. But I'm very grateful the camera wasn't on me just then. My heavens, if you didn't have tears in your eyes at that moment, what kind of human being are you?" Swanson is a gifted writer and masterful at handling a plot we think we know by heart.

In the 603 pages of this book by Larry J. Sabato, a politics professor at the University of Virginia, I found this chilling speculation: If President Lyndon Johnson had shown up at the 1968 Democratic convention in Chicago, he "probably would have turned the anger on Chicago's streets into complete anarchy." Kennedy's early years, his presidency and assassination are covered here in workmanlike fashion. The book's great value is its exploration of and attempt to explain how Kennedy's influence on politics has remained so strong.

It was pleasurable, mostly, to flip through this book. One letter written when he was 12 is a plea to his father to raise his allowance. In part it reads, "My recent allowance is 40 (cents). This I use for areoplanes (sic) and other playthings of childhood but now I am a scout and I put away my childish things."

For my money, the best Kennedy book is 1967's "The Death of a President"by William Manchester. The book was commissioned by Jacqueline Kennedy, who later demanded that passages she deemed too personal be cut from the manuscript. Those trims were minor, and the book has an intimacy and immediacy that no other book can match, thanks in large part to Manchester interviewing more than 1,000 people.

I will add this: Though published in 2011, Stephen King's"11-22-63" (and what a wonder no other author among those 40,000-some Kennedy books was clever enough to grab that title) is terrific. It's a thick but captivating novel about a 35-year-old high school English teacher from Maine who travels back in time to try to prevent the assassination.

I will leave you with this, published in The New Yorker a week after Kennedy's death.

When we think of him, he is without a hat, standing in the wind and the weather. He was impatient of topcoats and hats, preferring to be exposed, and he was young enough and tough enough to confront and to enjoy the cold and the wind of these times. ... It can be said of him, as of few men in a like position, that he did not fear the weather, and did not trim his sails, but instead challenged the wind itself, to improve its direction and to cause it to blow more softly and more kindly over the world and its people.

That was written by E.B. White, and in so many ways, that's good enough for me.